It has been commonplace for quite some time to produce laminated wooden beams for various structural purposes. Such structural members being characterized as having extremely strong shear and bending strengths have been used as beams, arches, trusses, columns, joists and girders.
The laminated wooden beams described above are generally constructed of rectangularly shaped sawn lumber, which are laminated to one another by gluing individual members and contacting said members with one another under high pressure to set the glue. The individual laminations are longitudinally disposed, thus possessing adjacent bonded surfaces running throughout the longitudinal dimension of the composite laminated member.
Although the composite member is ideally suited as a structural support, it has been found to be quite difficult, if not impossible, to establish a drilled hole within the body of the laminated beam along its longitudinal axis with any degree of precision. This is particularly true when the drilled hole is attempted to be made at the interface of adjacent individual wooden members due primarily to the presence of cured glue or adhesive. Growth characteristics of the wood such as knots, grain angle varying wood density, which are not symetrical to the axis of the bore, presents a substantial obstacle to the drilling of a cylindrically shaped hole at a precise predetermined location.
The desire for the establishment of cylindrically shaped holes within laminated wooden members formed with a degree of predetermined precision has been well recognized within the industry. For example, laminated wooden members, when used as trusses and girders, have occasionally been called upon to tie into still other similar structural members. This tie-in can be accomplished by setting a threaded member within the laminated wooden beam which thus can be threadably engaged with another structural member as a means of attachment. However, due to the problems outlined above in establishing a cylindrically shaped hole along the longitudinal direction of the laminated wooden beam as a receiving hole for the threaded member, the use of laminated wooden beams has been restricted as structural supports.
It is thus an object of the present invention to overcome the problems and difficulties outlined above.
It is yet another object of the present invention to establish a cylindrically shaped hole along the longitudinal axis of a laminated wooden beam with a degree of precision and accuracy unachievable by employing prior art techniques.